Collagens have been conventionally widely used as gelatins in the field of foods. Collagens, which are animal proteins, are main ingredients of dermis, connective tissues, or the like, so that the collagens have been in the limelight also in the aspects of medical fields or cosmetic fields in the recent years.
In general, it is considered to be difficult to efficiently utilize the ingested collagens in a body even when collagens having large molecular weights are orally ingested. However, in the recent years, collagen peptides in which high-molecular collagens are formed into low-molecular compounds to be suitably ingestible in a body have been developed, and beverages containing collagen peptides have also been developed.
Beverages containing collagen peptides as mentioned above have been classified as refreshing beverages, to which heat treatment has been carried out for the purpose of sterilization. The sterilization conditions are differentiated depending upon the pHs of beverages according to the Food Sanitation Act in Japan (Ministry of Health and Welfare, Announcement No. 213). It is described in the Food Sanitation Act as the production standards for those requiring sterilization, but without storage standards, that the sterilization for those at a pH of lower than 4.0 includes a method of heating a central part temperature to 65° C. for 10 minutes or a method equivalent or better thereof; and the sterilization for those at a pH of from 4.0 to 4.6 includes a method of heating at 85° C. for 30 minutes or a method equivalent or better thereof.
Regarding collagen peptide-containing beverages, Patent Publication 1 discloses a beverage composition realizing an appropriate sour taste and excellent flavor within a pH range of a pH 4.0 or lower which is effective for anti-corrosion, by including two or more kinds of acidulants including phosphoric acid to adjust its pH to 4.0 or lower. On the other hand, collagen peptides have been tried to be blended into beer-taste beverages. Patent Publication 2 discloses a technique in which the texture of foams in Happoshu is made even finer to keep rigidity of the foams even firmer, so that the foams would not disappear over a long period of time, thereby keeping a lingering taste of the Happoshu.